With the ever increasing stringent regulations relative to hazardous materials, users of such materials as organic solvents are required to contain any spillage or leakage from industrial drums and prevent pollution of underlying substrates and runoff of such materials to soil or water courses.
Examples of hazardous waste spill skids of the prior art are described in U.S. Pat. No. 4,838,178, U.S. Pat. No. 4,930,632, U.S. Pat. No. 5,020,667, U.S. Pat. No. 5,036,976, U.S. Pat. No. 5,092,251 and U.S. Pat. No. 5,147,039. In U.S. Pat. No. 4,838,178, a hazardous waste shipping pallet is shown which is preferably formed as a metal tray with a plywood platform. The shipping pallet has a planar base and a rigid support member fixedly mounted to the bottom surface of a container, and at least one internal load bearing rail fixedly mounted to the uppermost surface of the inside of the container, with a removable platform positioned on the load bearing rail. U.S. Pat. No. 4,930,632 shows a tray having a base and substantially vertical side walls to form a containment pan with the side wall upper edges lying in a common plane, the tray bottom wall having grooves to receive forks of a fork lift and reinforcement ribs between the grooves. A pallet support member rests in the tray and is formed of spaced apart beams and transverse rails attached to the beams to form a platform to support a storage pallet above the plane formed by the upper edges of the tray side walls. In U.S. Pat. No. 5,020,667, a rectangular chamber is formed by a polyethylene bottom and side walls, the side walls having a support ledge at the upper periphery thereof. A fiberglass grating is provided that has spaced bars shaped to direct spilled material into the chamber, and a polyvinyl or polyethylene support tube, preferably removable, is disposed in a central chamber of the rectangular chamber, with apertures in the tube to allow dispersal of spillage to other subchambers. U.S. Pat. No. 5,036,976, which is a continuation of the application which issued as U.S. Pat. No. 4,930,632 has a tray similar to the tray of that earlier patent and a pallet support member which rests in the tray, the pallet support member comprising at least one support member received within the tray and resting on the bottom wall and a platform member supported by the support member to form a platform substantially at the level of the plane formed by the tray side wall upper edges, so as to provide support for a storage pallet adjacent to or above that plane. In U.S. Pat. No. 5,092,667, a rotationally molded integral pallet and platform are described, with a basin beneath the platform, the platform having an undulating cross-section and a plurality of holes passing through the platform to permit leakage from drums supported on the platform to enter the basin. A center post may extend from the bottom wall of the base of the basin to a position adjacent the platform to support the platform at the center thereof. U.S. Pat. No. 5,147,039, which is a continuation of the application from which U.S. Pat. No. 5,036,976 issued, shows a containment tray having a floor and vertical side walls and a removable support structure insertable into the tray and resting on the floor, the removable support comprising a plurality of upright support members resting on the floor and a plurality of members positioned on the support members to form a generally horizontal support platform on which a palletized load of containers may be positioned.
Applicants are also aware of a spill pallet available commercially which has a polyethylene tray with four walls and a central support extending between two opposed walls of the tray and central extensions extending from the central support in the direction of the other two walls. The central support has an upward ridge therealong which divides the tray into two sections, with a solid grate resting in each of the two sections of the unit, on a wall ledge and on the central support, adjacent the upward ridge, and on one of the central extensions.